Ok, here we are. The code is for 1.5 ( I have no idea how it must look under 1.0, but I believe you can find that out)
The function you need is in components/com_comment/joscomment/comment.class.php
function form_htmlCode() at around 2902.
So go the end of the function right before the return html and add:
$module = &JModuleHelper::getModules('left');
$attribs = array('style' => 'xhtml');
foreach ($module as $mod) {
$html .= JModuleHelper::renderModule($mod,$attribs);
}
this will load all modules in the left menu(for 1.5) and will show them after the !jocomment post form.
If you want to place the module on a nother place, just go up in the function.
Have fun!
Daniel